CALCULATIONS OF THE 2ND VIRIAL-COEFFICIENT AND OF THE TRANSPORT-PROPERTIES USING BSSE-CORRUPTED AB-INITIO POTENTIALS

We have estimated bulk properties of the Ar2 van der Waals complex usi ng ab initio potentials in an effort to assess the validity and reliab ility of a partial counterpoise correction (extended indirect counterp oise (EICP)) previously proposed (S. Tolosa, J. Espinosa and F.J. Oliv ares del Valle, J. Comput. Chem., 12 (1991)611) to avoid the basis set superposition error. Three types of potentials are used (uncorrected, full-counterpoise (CP) corrected and EICP corrected) to estimate the second virial coefficient and transport properties in the van der Waal s association Ar2. It is found that the EICP correction provides a mor e satisfactory response than the CP correction under the same working conditions (basis set, level of calculation, etc.), especially in the repulsive zone and in the minimum of the potential. This conclusion ma y be particularly relevant when more complex systems are studied, for which calculations using large basis sets (with f- or g-type functions ) or higher MP terms are very expensive in terms of computer use.